1. Field of the Invention
The present invention generally relates to techniques for detecting the onset of severe wind and, more particularly, is concerned with a wind detecting and alerting apparatus.
2. Description of the Prior Art
Communities across the United States rely on the National Weather Service for advance warning of the approach of severe and dangerous weather carrying high winds, such as thunderstorms and tornados. The warning typically covers a large region and is broadcast by radio and television stations whose signals are received in the region. Also, some communities have sirens which are sounded to convey the warning.
However, oftentimes the warning arrives after the damaging high winds have already passed through some local communities in the region and caused considerable damage to property and injury or death of individuals. There is no guarantee in any localized community that the warning will arrive soon enough to permit people to take appropriate precautions and protective shelter.
Attempts have been made in the prior patent art to design devices to detect when the wind velocity exceeds a particular value. One such wind detection device is disclosed in U.S. Pat. No. 4,034,174 to McCord. The wind detection device of the McCord patent employs a hollow standpipe mounted upright on a support structure, such as a roof, by a bracket, and a hollow wind tube rotatably secured by a bolt and bushing to an upper end of the standpipe. Within the wind tube is a flared metal disc attached to a leaf spring switch actuator which, in turn, is part of a switch on a housing. The housing is mounted by a bracket near to a forward open end of the wind tube, while a wind vane responsive to wind direction is mounted by a bracket to a rear open end of the wind tube.
The wind detection device of the McCord patent also includes an electrical circuit containing an alarm and battery connected in series with one another and with the spring switch actuator on the switch housing. An electrical wire of the circuit is routed from the switch housing down along the exterior of the standpipe to the bracket mounting the standpipe and therefrom through the roof to the location where the wire is connected to the alarm and battery. A stop bracket is attached to the wind tube adjacent its pivotal axis and a stop pin is mounted on the standpipe. The stop bracket and pin cooperate to limit the wind tube to a single revolution about its axis in order to avoid entanglement or wrapping of the electrical wire about the standpipe. One or more slip rings may be used in the electrical circuit instead of the external wire in order to obviate the need for the stop bracket and pin.
In operation, wind blowing on the wind vane of the wind tube of the wind detection device causes the wind tube to rotate and point in the wind's direction. The disc on the spring switch actuator will thus face the wind directly, regardless of the wind's direction. The force of the wind acts on the disc tending to move it, with the configuration of the spring switch actuator providing the force resisting such movement. By changing either the size of the disc or by bending the spring switch actuator, the wind velocity need to move the disc and thus to actuate the switch within the housing can be varied.
While the McCord wind detection device may be a step in the right direction, it does not nearly approach an optimum design for devices of this nature. The abovedescribed construction of the McCord device appears to have several drawbacks which will adversely affect its reliability over time and will require periodic service check-ups and maintenance.
One drawback is that the open-ended hollow wind tube will not only receive the blowing wind but also debris and foreign matter carried by the wind. Birds might also find the open-ended hollow wind tube to be an attractive site for building a nest. In any event, it is likely that debris will tend to accumulate within the tube and on the disc and spring switch actuator and eventually adversely affect the operation of the switch. As a result, the ability of the switch to respond to wind velocity exceeding a particular value cannot be assured at any given time.
Another drawback is that the relative moving components of the device are exposed to the adverse elements of the environment which means that they will require frequent lubrication and maintenance to ensure that they are in operative working condition. This will require that frequent trips be made to the top of the roof to service the device.
In view of these shortcomings of the McCord device, a need still remains for more improvements in techniques for detecting the onset of severe wind.